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For a project outside the U.S., how do I determine the Target Finder score?

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The Section 9 space-by-space method does not include residential space types. What should I use?

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Our project has a large process load—75%. Despite our efforts to make an efficient HVAC design, the cost savings are minimal. What can we do to earn this prerequisite and be eligible for LEED certification? Is there any flexibility in how we model the p

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Forum discussion

CS-2009 EAp2:Minimum Energy Performance

If some facades meet ASHRAE 90.1, but others don't....

....does the project meet ASHRAE 90.1's Mandatory Provisions and therefore this Prerequisite? Our project has complicated set of facades with different curtain-wall patterns and types of glass. Two of those facade directions comply with the ASHRAE "Mandatory Provisions" requirements for SHGC, while the other two do not: the requirement is a SHGC for each facade of 0.25 and two facades are 0.203 and 0.245...the others are 0.266 and 0.264. Will this project be rejected for this prerequisite based on these figures?

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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Mon, 05/13/2013 - 00:35

SHGC is not a mandatory provision. It is available for trade-off.

Mon, 05/13/2013 - 05:34

That's good to hear. So a "trade-off" basically means that we can have a deficit in one area/facade as long as it is made up in another area: as long as we balance out with an overall performance that meets the standard we are ok? For example: if the requirement is 0.25 for all facades and we have 0.20 for two facades and 0.30 for the other two, then we are compliant.....did I understand that correctly? Thanks in advance.
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Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Mon, 05/13/2013 - 12:33

Trade-off means you can exceed a prescriptive requirement of 90.1, like SHGC, by as much as you want. You do not need to balance some under SHGC with some over. Trade-off is general and not specific. Basically you are trading-off being over the SHGC for some glass with exceeding the prescriptive requirements in other areas, could be some other glass SHGC or higher insulation or greater cooling efficiency, etc.. The trade-off is against other energy saving measures. The only requirement is that you be able to show the minimum energy savings required by the LEED prerequisite.

Mon, 05/13/2013 - 13:13

Thank you Marcus! This makes so much more sense now. Why is ASHRAE's writing so cryptic? To be answered another day.

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